Nanosheet-Assembled NiO Microstructures for High-Performance Supercapacitors

Abstract

Nanosheet-assembled NiO microstructures have been synthesized via a hydrothermal method. The presence of anionic surfactant in the fabrication process initiates the formation of lamellar micelles and a self-assembling process. This leads to the formation of NiO nanosheets and organizes it into microstructures. The effect of preparation temperature on the morphological, structural, and electrochemical properties and stability upon continuous charge/discharge cycles has been examined for supercapacitor applications. Electrochemical analysis demonstrated that NiO nanosheets prepared at 160 °C are capable of delivering a specific capacitance of 989 F g(-1) at a scan rate of 3 mV s(-1) for the potential window of 0-0.6 V. The nanosheets exhibit excellent capacity retention, 97% retention after 1000 continuous charge/discharge cycles, and an energy density of 49.45 W h kg(-1).

In situ preparation of NiO nanoflakes on Ni foams for high performance supercapacitors

“…3a shows the SC values of the corresponding CV curves. The SC of the composite is 1784.2 F/g at 5 mV/s, which is near the theoretical SC value of NiO [13] and is a high value compared with the reported works (989 F/g at 3 mV/s [14], 644 F/g at 2 mV/s [15]). The SC value of the composite still has 693.1 F/g at a high san rate of 100 mV/s, making it a promising material for supercapcitors at high charge/discharge current.…”

Facile hydrothermal synthesis of flowerlike ZnCo 2 O 4 microspheres as binder-free electrodes for supercapacitors

“…Thus far, ZnCo 2 O 4 materials with various nanostructures have been prepared such as nanowires [10], nanorods [11], nanotubes [12], and nanosheets [13], and the capacitors based on them can show greatly enhanced electrochemical performances. Microspheres composed of nanosheets can obtain enhanced electrochemical performances, which is due to large amount of diffusion paths for electrolyte ions within the microspheres [14]. Yolk-shelled [15] and mesoporous [16] …”

Hierarchical CuCo2O4 nanobelts as a supercapacitor electrode with high areal and specific capacitance

“…This Rs value is the combination of ionic and electronic resistance, intrinsic resistance of the CuCo2O4 electrode, and diffusive and contact resistance at CuCo2O4 electrode/current collector interface. The semicircle at high frequency region is related to the charge transfer resistance (Rct), due to the Faradic redox reaction of the electrode[36]. The Rct value of the electrode is 3.85 Ω.…”

“…This low Rct value enhances the supercapacitor performance of highly ordered CuCo2O4 nanowires electrodes. The straight line portion in the low frequency region corresponds to Warburg resistance[36]. The high capacitance, low resistance, and long cycle life demonstrate the CuCo2O4 nanobelts are promising electrode material for supercapacitor applications.…”